gocover-cobertura

README

Forked from t-yuki

This is a fork of https://github.com/boumenot/gocover-cobertura.

At the time of this writing the repository appears to be on pause with several outstanding PRs, and forks with interesting contributions. This repo consolidates those outstanding forks, and combines them into one repo.

[2026-05-01]: This project has evolved from a private fork created for my own needs into something that is now used by many others. Historically, I have not focused heavily on maintaining this repository—I’ve occasionally merged PRs or made fixes, but for my purposes, the functionality was “good enough.”

However, that context has changed. While this fork met my original goals, it is now clear that others are relying on it. As a result, I feel a greater sense of responsibility for its quality and stability.

To address this, I plan to strengthen the repository by introducing a regression test suite based on popular open-source Go projects. The current test coverage is minimal and needs improvement. Although several PRs have identified issues, the lack of comprehensive testing makes it difficult to confidently ensure that new changes do not introduce regressions.

The goal of the regression suite is to lock in current behavior and enable more deliberate, explicit decisions when making changes. I also hope to extract simplified reproductions from identified issues, which should help improve long-term maintainability (AI has been especially helpful in this area).

I don’t expect to spend much more time here, but I will be more intentional about stewardship now that others depend on it.

go tool cover XML (Cobertura) export

This is a simple helper tool for generating XML output in Cobertura format for CIs like Jenkins and others from go tool cover output.

Installation

Just type the following to install the program and its dependencies:

$ go get github.com/boumenot/gocover-cobertura

Usage

gocover-cobertura reads from the standard input:

$ go test -coverprofile=coverage.txt -covermode count github.com/gorilla/mux
$ gocover-cobertura < coverage.txt > coverage.xml

Note that you should run this from the directory which holds your go.mod file.

Windows note: PowerShell does not support the < operator for stdin redirection. Use piping instead:

Get-Content coverage.txt | gocover-cobertura > coverage.xml

In cmd.exe, < works but may cause encoding issues with non-ASCII file paths. The piping approach above avoids this problem on both shells.

Flags

Some flags can be passed (each flag should only be used once):

• -by-files

  Code coverage is organized by class by default. This flag organizes code coverage by the name of the file, which the same behavior as go tool cover.

• -ignore-dirs PATTERN

  ignore directories matching PATTERN regular expression. Full directory names are matched, as github.com/boumenot/gocover-cobertura (and so github.com/boumenot and github.com), examples of use:

  # A specific directory
  -ignore-dirs '^github\.com/boumenot/gocover-cobertura/testdata$'
  # All directories autogen and any of their subdirs
  -ignore-dirs '/autogen$'
  

• -ignore-files PATTERN

  ignore files matching PATTERN regular expression. Full file names are matched, as github.com/boumenot/gocover-cobertura/profile.go, examples of use:

  # A specific file
  -ignore-files '^github\.com/boumenot/gocover-cobertura/profile\.go$'
  # All files ending with _gen.go
  -ignore-files '_gen\.go$'
  # All files in a directory autogen (or any of its subdirs)
  -ignore-files '/autogen/'
  

• -ignore-gen-files

  ignore generated files. Typically files containing a comment indicating that the file has been automatically generated. See genCodeRe regexp in ignore.go.

• -ignore-non-code-lines

  ignore lines with no code. The coverage report generated by go tool cover includes some lines with no code. This flag strips lines with no code from coverage data.

• -path DIR

  set the project directory for package resolution. By default, gocover-cobertura resolves packages relative to the current working directory. Use this flag when running from a different directory than the module root, for example in monorepos with nested modules:

  gocover-cobertura -path /repo/services/api < coverage.txt > coverage.xml
  

• -strict

  exit with an error if any profiles are skipped due to missing package or module information. By default, skipped profiles produce warnings on stderr but the tool exits successfully. Use this flag in CI pipelines to catch silent data loss:

  gocover-cobertura -strict < coverage.txt > coverage.xml
  

Build tags

If your tests use build tags, you must pass the same tags when running gocover-cobertura. The tool uses packages.Load to resolve source files, and it needs matching tags to find the right files.

Pass tags via the GOFLAGS environment variable:

# Single tag
GOFLAGS="-tags=integration" gocover-cobertura < coverage.txt > coverage.xml

# Multiple tags
GOFLAGS="-tags=integration,e2e" gocover-cobertura < coverage.txt > coverage.xml

On Windows (PowerShell):

$env:GOFLAGS="-tags=integration"; gocover-cobertura < coverage.txt > coverage.xml

Why is this needed? When you run go test -tags=integration -coverprofile=coverage.txt, the coverage profile includes files that are only compiled with that tag (e.g. files with //go:build integration). Without the matching tag, gocover-cobertura cannot locate those files and will skip them with a warning on stderr.

Troubleshooting

Warning: skipping profile — no package/module information available

This warning means gocover-cobertura could not resolve a package from the coverage profile. Common causes:

• Missing build tags — see Build tags above.
• Wrong working directory — run from the directory containing go.mod, or use the -path flag.
• Standard library packages — coverage profiles occasionally include stdlib packages, which have no module info. These are safely skipped.

Warning: skipping profile — unable to determine file path

The package was resolved but a specific source file was not found. This typically happens when the coverage profile was generated on a different platform (e.g. _windows.go files in a profile generated on Windows, but the converter is running on Linux). These files are safely skipped.

Branch coverage is always 0

The Cobertura format supports branch coverage (branch-rate, branch="true" on lines), but gocover-cobertura always reports branch-rate="0".

Go's coverage instrumentation tracks which statement blocks were executed, not which branch paths were taken. While branch points (if/else, switch) can sometimes be inferred from block boundaries, Go does not produce enough structural information to reliably count the number of branch arms at a decision point. Reporting inaccurate branch coverage would be worse than reporting none, so this tool leaves branch-rate at 0.

Regression Tests

A snapshot-based regression test suite verifies that conversion output remains stable across code changes. The suite converts real coverage profiles from open-source Go projects and compares the XML output against checked-in golden files. Each regression fixture validates the default output against golden.xml and the -ignore-non-code-lines output against golden-ignore-non-code-lines.xml.

Running regression tests (Linux only):

go test -tags regression -run TestRegression -v -timeout 600s

Updating golden files after intentional changes:

go test -tags regression -run TestRegression -update -v -timeout 600s
git diff testdata/regression/  # review the changes

Platform note: Golden files are generated on Linux. The regression tests are skipped on non-Linux platforms because coverage profiles may reference platform-specific source files (e.g. _windows.go) that are unavailable on other operating systems. To regenerate golden files on Windows, use WSL.

Current corpus:

Project	Tag	Lines
gorilla/mux	v1.8.1	946
spf13/cobra	v1.8.1	4,420
approvals/go-approval-tests	v1.9.1	1,785
junegunn/fzf	v0.60.0	14,137
stretchr/testify	v1.10.0	3,196
prometheus/prometheus	v3.2.0	78,123
kubernetes/kubernetes	v1.32.0	26,956

AuthorsMerger

Christopher Boumenot (boumenot)

Thanks

• Yukinari Toyota (t-yuki)
• This tool is originated from gocov-xml by Alexey Palazhchenko (AlekSi)
• DarcySail's PR
• maxatome's PR
• elliotmr's branch